Toxicity of Inorganic and Organic Selenium to Daphnia Magna (Cladocera) and Chironomus Riparius (Diptera)

Abstract

Elevated concentrations of selenium (Se) have been previously measured in biota sampled from the Kesterson National Wildlife Refuge (KNWR) in the San Joaquin Valley of central California. We conducted acute and chronic toxicity tests with the cladoceran Daphnia magna and the midge Chironomus riparius to determine the toxicity or bioaccumulation of waterborne Se in a reconstituted water sinilar to the San Joaquin River. Daphnids were more acutely sensitive than midges to the toxic effects of inorganic Se. An organic form of Se (seleno-[L]-methionine) was extremely toxic to daphnids, but was relatively nontoxic to midges. In long-term exposure to a 6:l mixture of selenate to selenite (a mixture representative of KNWR), the emergence time of adult midges was delayed at Se concentrations 2 837 pg/L. Daphnid reproduction and intrinsic rate of natural increase ( r ) were reduced at Se concentrations 2 348 pg/L and growth of adults was reduced at 2156 pg/L. Whole body Mg, K and Na concentrations in daphnids were not affected by chronic Se exposure; however, whole body Ca concentration increased at intermediate Se exposure concentrations. In addition, whole body C1 concentration was reduced at 71 1 pg Se/L. Daphnids accumulated potentially toxic concentrations of Se from water that may adversely affect fish or waterfowl through the food chain.

Toxicity and bioaccumulation of selenium to a three‐trophic level food chain

“…Our results support the work of earlier researchers [13,14,17,18,37,38] who found that Se had a negative impact on aquatic biota at concentrations Ͻ100 g/L, and as low as 10 g/L in some food chain studies. Most studies have found fish to be sensitive to Se only under conditions of long-term exposure from both food and water.…”

Influence of stability on the acute toxicity of CdSe/ZnS nanocrystals to Daphnia magna

“…Selenium was not successfully measured in many of the QD exposure solutions due to high Se detection limits on the ICP-AES. However, selenium was not seen as important in the acute toxicity of QDs, because the total selenium concentrations in even our highest QD treatments were below toxicologically relevant concentrations for acute tests [24].…”

Toxicity of Selenomethionine- and Seleno-Contaminated Sediment to the Amphipod Corophium sp.

“…and the epibenthic amphipod P. australis in water-only exposures. Ingersoll et al (1990) referred to the similar extreme acute sensitivity of Daphnia magna to selenomethionone, although the toxicity of selenomethionone was not studied in detail.…”

“…The toxicity risk posed by selenium is primarily from dietary uptake, which is a result of the propensity of selenium to cycle through the sediment and enter the benthic}detrital food web. This dietary uptake of selenium ultimately causes growth and reproductive impairment in "sh, crustaceans, and other wildlife (Ahsanullah and Brand, 1985;Hamilton et al, 1990;Ingersoll et al, 1990). The chronic toxicity of the seleno-amino acids to Corophium sp.…”

“…Selenomethionine is more bioavailable than inorganic selenium, is rapidly accumulated by biota (Sandholm et al, 1973;Besser et al, 1993), and is more toxic (Niimi and La Ham, 1976;Ki!ney and Knight, 1990;Ingersoll et al, 1990;Maier et al, 1993). Thus, organoselenides may pose a disproportionately higher risk of direct toxicity and reproductive e!ects than selenite or selenate .…”